Sunday, April 22, 2007

Theory of Everything (”TOE”) unifies the four fundamental interactions of nature: gravity, the strong nuclear force, the weak nuclear force, and the electromagnetic force; it should also explain the spectrum of elementary particles. There has been progress toward a TOE in unifying electromagnetism and the weak nuclear force in an electroweak unified field theory and in unifying all of the forces except for gravity (which in the present theory of general relativity is not a force) in the grand unification theory. One missing piece in a theory of everything involves combining quantum mechanics and general relativity into a theory of quantum gravity.